Open-source alternatives to Cling

Wasm3 is a WebAssembly interpreter designed for embedded runtime integration. It enables the execution of portable binary logic on microcontrollers and resource-constrained hardware, providing support for modules that utilize the WebAssembly System Interface to interact with system resources. The runtime employs register-based bytecode interpretation and direct-threaded dispatch to map virtual registers to physical CPU registers. It includes a host-call interface to map imports to C functions and utilizes static module validation to ensure bytecode follows specification rules before execution

PsySH is an interactive read-eval-print loop and shell environment for PHP. It functions as a runtime debugger and application inspector, allowing for the execution of PHP code in real-time to experiment with snippets and inspect live application state. The project is distinguished by its ability to be embedded directly into running PHP applications for live troubleshooting. It provides specialized tools for state manipulation, including the ability to bypass visibility restrictions to inspect private or protected object members and the capacity to reload code without restarting the session.

IPython is an interactive computing environment and programmable extension of the Python read-eval-print loop. It serves as a development tool for writing, testing, and executing code in a live environment designed for rapid prototyping and data exploration. The system differentiates itself through a specialized set of magic commands for environment configuration and system shell integration. It features an object introspection engine for analyzing live program objects at runtime and a frontend-agnostic kernel that allows the execution logic to be embedded into other applications or graphical

Devtool is a suite of developer tools designed to execute server-side JavaScript code within a browser environment. It functions as a bridge that allows Node.js programs to run inside a Chromium instance, enabling the use of built-in browser developer tools for visual debugging and performance profiling. The project provides a read-eval-print loop for interactive command execution with support for relative imports and piped input. It also includes a file watcher that monitors source files for changes and automatically reloads programs to accelerate the iteration cycle. The system integrates

Pry is a programmable Ruby shell, REPL console, and runtime developer environment. It serves as a debugging toolkit for inspecting object state, navigating bindings, and evaluating code within a running Ruby program. The project differentiates itself through advanced introspection and live iteration capabilities. It allows users to inject an interactive console into a running program at specific points to inspect local state and navigate different object scopes. It further enables live code iteration by integrating with external system editors to modify and reload method definitions without r

Hy is a Lisp implementation for Python that allows for writing Lisp syntax which compiles to Python bytecode. It operates as a Python-based Lisp dialect and S-expression language, providing full access to the Python standard library and ecosystem. The language focuses on macro-based metaprogramming, featuring an AST-walking macro system and reader macros that allow for custom syntax transformations and parsing rules. It enables the manipulation of the abstract syntax tree to extend language capabilities. The project includes a read-eval-print loop for interactive development and supports sta

Unicorn is a multi-architecture CPU emulation framework and library that utilizes just-in-time compilation to execute instructions across various processor architectures, including ARM, x86, and RISC-V. It functions as both a JIT compilation engine and an instrumentation tool, allowing for the execution of machine code without the need for physical hardware. The framework is distinguished by its hook-based execution instrumentation, which enables the interception of specific instructions and memory accesses to trigger custom callback functions. It provides a language-agnostic binding layer an

fsql is a command line interface tool that provides a SQL-like query language for finding files and directories on a local disk. It functions as a filesystem query engine, allowing users to isolate files by executing structured statements against metadata instead of using standard command line flags. The tool features an interactive read-eval-print loop that supports multi-line queries and recursive subqueries, where the results of nested search operations serve as criteria for outer queries. Search scopes are configurable through the resolution of absolute paths, relative paths, environment

Blink is a JIT-based instruction emulator and x86-64 Linux emulator designed to run Linux binaries and ELF files across different host operating systems and architectures. It functions as a binary execution sandbox and system call simulator, providing a controlled environment for running programs. The project distinguishes itself with a terminal user interface for monitoring execution, managing breakpoints, and visualizing JIT compilation paths. It supports self-modifying code through a cache-invalidating memory model and provides execution environment isolation using restricted directory ove

ts-node is a TypeScript execution engine and just-in-time transpiler for Node.js. It enables the direct execution of TypeScript files by converting them to JavaScript on the fly, removing the requirement for a manual pre-compilation build step. It also provides a TypeScript read-eval-print loop for evaluating expressions and testing code snippets in real time. The project integrates with the Node.js module system as a loader hook to resolve and load files using native import syntax. It features a pluggable compiler interface that allows the use of external transpilers to accelerate execution

CoreCLR is a runtime environment that manages the execution, memory, and basic types for applications built on the .NET platform. It serves as a managed execution environment that handles low-level system interactions and provides primitive data types for high-level application code. The project functions as a JIT compilation engine and a garbage collected runtime. It translates intermediate language into machine code at runtime for execution on specific hardware and automatically reclaims unused memory to prevent leaks. The system covers broad capability areas including managed code executi

Fiddle is an interactive API reference tool and playground environment for the Electron platform. It serves as a project prototyper and sandbox where users can explore, draft, and test application logic without the need to manually set up a full project structure. The tool distinguishes itself by allowing users to compile prototype experiments into distributable standalone binaries for Windows, macOS, and Linux. It also provides a mechanism to export these experiments into standalone project folders for continued development in a professional integrated development environment. The environme

ClojureScript is a Lisp-based compiler and runtime that translates Clojure source code into JavaScript. It enables functional programming across different JavaScript engines and platforms, allowing developers to build user interfaces and applications for web browsers and server environments. The project provides a read-eval-print loop for executing code live within a browser or server for immediate feedback. This facilitates an interactive development workflow where code can be written and tested in real time without restarting the application. The system covers a broad capability surface, i

aws-shell is an interactive command-line environment designed for executing AWS CLI commands. It functions as a wrapped shell that allows users to run provider-specific infrastructure commands and local system processes within a single interface. The tool distinguishes itself through fuzzy-matching autocomplete for commands and resource IDs, along with dynamic inline documentation and help panels that provide immediate syntax guidance. It enables rapid context changes by allowing users to switch between different AWS identity profiles during a single session. The environment includes session

Leiningen is a build tool, dependency manager, and project automator for Clojure. It provides a command-line interface for bootstrapping new project structures, managing external libraries, and launching interactive read-eval-print loops for live development. The tool allows for the extension of build commands through a plugin system and manages project settings using a configuration map that can be layered with global user preferences and specific profiles. Its capabilities cover the full project lifecycle, including automated test execution, the creation of standalone executable archives,

Node.js is an open-source, cross-platform JavaScript runtime environment built on the V8 engine, designed for executing JavaScript code outside a web browser. It operates as a server-side JavaScript platform with an event-driven, non-blocking I/O architecture that enables building scalable network applications and web servers. The runtime integrates the CommonJS module system for synchronous module loading and the npm ecosystem for sharing and reusing packages. The platform provides comprehensive capabilities for web server development, including creating HTTP and HTTPS servers, managing HTTP

MicroPython is a lean implementation of Python 3 optimized to run on microcontrollers and other resource-constrained systems. It serves as a cross-platform embedded runtime and hardware abstraction layer, providing a firmware framework that maps high-level software commands to specific microcontroller registers across diverse processor architectures. The project functions as an embedded language interpreter that enables rapid prototyping on hardware through an interactive read-eval-print loop. It supports a wide range of target environments, including ARM, ESP32, STM32, RISC-V, and WebAssembl

AsmJit is a runtime machine code generator and JIT compiler backend that translates high-level definitions into executable processor instructions. It provides a unified instruction emission API and an executable memory manager to allocate and protect virtual memory pages across multiple CPU architectures. The library functions as an assembly engine for x86 and ARM, supporting cross-platform assembly generation through a unified backend. It enables the creation of optimized machine code for different CPUs while maintaining a single codebase. The project covers low-level system abstractions in

This project is an exercise-based learning platform and functional programming course designed to teach Haskell through a structured curriculum of practical implementation tasks. It functions as an interactive tutorial and learning framework where students master functional programming concepts by completing a curated sequence of modules. The platform emphasizes a type-driven development workflow, utilizing type holes and compiler-integrated type querying to guide the discovery of program logic. It provides an interactive programming environment via a read-eval-print loop, allowing for real-t

Shell GPT is an AI-powered command-line interface that generates shell commands and source code from natural language prompts. It serves as a terminal-based tool for automating technical tasks, producing executable commands, and generating code snippets directly within the shell. The tool distinguishes itself through a read-eval-print loop for interactive chatting and the ability to maintain stateful conversational history via named sessions. It supports flexible backend routing, allowing users to connect to cloud-based APIs or local language model hosts for offline operation and data privacy

PyWebIO is a Python web application framework and script-based UI library that allows the construction of interactive web interfaces without writing HTML, CSS, or JavaScript. It treats the web browser as a rich terminal, translating Python function calls into UI elements and capturing user input through a synchronous request-response loop. The framework functions as an asynchronous web app server that executes user sessions as coroutines to handle multiple concurrent interactions on a single thread. It also serves as a data visualization interface, enabling the direct rendering of interactive

Wasmtime is a WebAssembly runtime and sandboxed bytecode executor designed to run WebAssembly bytecode on a host system. It functions as an embeddable engine that integrates into applications through native APIs and language-specific bindings, as well as a standalone execution environment accessible via a command line interface. It is a WASI compatible runtime, implementing the WebAssembly System Interface to provide portable access to system resources. The engine utilizes a JIT compilation model to translate intermediate representation into optimized machine code for various CPU architecture

Playroom is a frontend design system tool and JSX component sandbox. It functions as a UI component workbench and TypeScript-aware prototyper, allowing developers to design and test user interfaces within a live, interactive environment. The project enables visual testing by rendering the same component across multiple themes, screen sizes, and property configurations simultaneously. It provides a mechanism for interactive style guides and design system documentation, where components can be prototyped using an existing library and exported as a distributable sandbox. The workbench includes

Blade-build is a multi-language build system and software orchestrator designed to automate the compilation, linking, and testing of complex codebases. It functions as an incremental build engine that models project structures as directed acyclic graphs, ensuring that only affected modules are recompiled when source code or header files change. By utilizing declarative build specifications, the system provides a unified approach to managing dependencies and toolchains across diverse programming environments. The system distinguishes itself through a focus on hermetic build environments and re

handcalcs is a mathematical documentation generator and Python LaTeX calculation renderer. It serves as an automated calculation sheet tool that converts Python code and numeric calculations into formatted LaTeX mathematical documentation, functioning as both a symbolic math formatter and a Jupyter notebook math extension. The project transforms Python variable names into Greek symbols, subscripts, and standard mathematical notation. It converts code into formatted mathematical expressions that display the original formula, the numeric substitution, and the final result, allowing for the crea

EvalXR is an interactive Rust compiler that compiles code into dynamically loaded libraries for iterative evaluation without restarting the process. It serves as a Rust Jupyter kernel, a notebook runtime, and a REPL environment, all with state retention across evaluations. The project provides a stateful Rust evaluation engine that runs code snippets in isolated sandboxes while keeping functions and variables alive between executions. It supports cell-based execution, compiling Rust code into a shared library and loading it into the same process to preserve state, with an error-aware compilat

Kotlin Jupyter is an interactive computing environment that enables the execution of Kotlin code within Jupyter notebooks. It functions as a kernel for the Java Virtual Machine, providing a platform for data analysis, rapid prototyping, and scientific computing research. The system manages the evaluation of code snippets by compiling them dynamically at runtime, allowing for real-time interaction and variable inspection. The project distinguishes itself through a sophisticated code transformation pipeline that intercepts and modifies user input to support custom syntax and automated logic. It